Hindered rotation in some organometallic carbamates, thiocarbamates, and dithiocarbamates

Yoder, Claude H.; Komoriya, Akira; Kochanowski, John E.; Suydam, Fred H.

doi:10.1021/ja00753a030

Cited by 44 publications

(11 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Considering the proposed mechanism (Scheme ), the formation of 4 iso versus 4 would be determined by the regioselectivity of the second OCS insertion and subsequent silyl-group migration. Our finding of preferential silyl-group migration to oxygen versus sulfur is consistent with previous studies showing that insertion reactions involving silylamines and carbonyl sulfide preferentially form O-silyl products …”

Section: Resultssupporting

confidence: 92%

Chalcogen Extrusion from Heteroallenes and Carbon Monoxide by a Three-Coordinate Rh(I) Disilylamide

et al. 2015

View full text Add to dashboard Cite

We report the reactions of several heteroallenes (carbon disulfide, carbonyl sulfide, and phenyl isocyanate) and carbon monoxide with a three-coordinate, bis(phosphine)-supported Rh(I) disilylamide (1). Carbon disulfide reacts with 1 to afford a silyltrithiocarbonate complex similar to an intermediate previously invoked in the deoxygenation of CO2 by 1, and prolonged heating affords a structurally unusual μ-κ(2)(S,S'):κ(2)(S,S')-trithiocarbonate dimer. Carbonyl sulfide reacts with 1 to afford a structurally unique Rh(SCNCS) metallacycle derived from two insertions of OCS and N-to-O silyl-group migrations. Phenyl isocyanate reacts with 1 to afford a dimeric bis(phenylcyanamido)-bridged complex resulting from multiple silyl-group migrations and nitrogen-for-oxygen metathesis, akin to reactivity previously observed with carbon dioxide. The ability of 1 to activate carbon-chalcogen multiple bonds via silyl-group migration is further supported by its reactivity with carbon monoxide, where a nitrogen-for-oxygen metathesis is also observed with expulsion of hexamethyldisiloxane. For all reported reactions, intermediates are observable under appropriate conditions, allowing the formulation of mechanisms where insertion of the unsaturated substrate is followed by one or more silyl-group migrations to afford the observed products. This rich variety of reactivity confirms the ability of metal silylamides to activate exceptionally strong carbon-element multiple bonds and suggests that silylamides may be useful intermediates in nitrogen-atom and nitrene-group-transfer schemes.

show abstract

Section: Resultssupporting

confidence: 92%

Chalcogen Extrusion from Heteroallenes and Carbon Monoxide by a Three-Coordinate Rh(I) Disilylamide

et al. 2015

View full text Add to dashboard Cite

show abstract

“…63 kJ mol À1 ), the dialkyldithioester molecule is planar and the nitrogen substituents are magnetically nonequivalent [30][31][32]. For this reason, the proton NMR spectrum of DMDTM in deuterated chloroform contains two distinct singlets for the methyl groups bound to nitrogen (3.55 and 3.38 ppm), along with the SCH 3 singlet at 2.64 ppm, palladium coordination causing a general downshift [29].…”

Section: Resultsmentioning

confidence: 99%

Pyrrolidine dithiocarbamates of Pd(II)

Faraglia

Sitran

Montagner

2005

Inorganica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…Compounds were obtained following the procedures described by Yoder et al 4949 Methyl N,N-dimethylcarbamate (1) was prepared by the reaction of sodium methoxide with N,Ndimethylcarbamoyl chloride in tetrahydrofuran (THF) (bp 128 °C/ ∼760 Torr, lit. 49 130-132 °C/∼760 Torr). 1 H NMR (300 MHz, CDCl 3 ) δ: 3.69 (3H, s); 2.91 (6H, s).…”

Section: Methodsmentioning

confidence: 99%

Medium Effect on the Rotational Barrier of Carbamates and Its Sulfur Congeners

2007

View full text Add to dashboard Cite

The solvent effect on rotation about the conjugated C-N bond has been studied for methyl N,N-dimethylcarbamate (1), S-methyl N,N-dimethylthiocarbamate (2), O-methyl N,N-dimethylthiocarbamate (3), and methyl N,N-dimethyldithiocarbamate (4). The present investigation included experimental determination of activation parameters (DeltaH, DeltaS, and DeltaG) combined with theoretical calculations via both quantum and classical approaches. Rotational barriers were measured through dynamic NMR experiments in solvents of varied polarity and proton donor ability. In the less polar solvents, the values were 15.3+/-0.5 (CS2), 14.0+/-1.1 (CS2), 17.5+/-0.4 (CCl4), and 14.6+/-0.5 kcal/mol (CCl4) for 1, 2, 3, and 4, respectively. Upon changing to an aqueous solution, the greatest variations occurred for 2 and 4, whereas for 1 and 3, there was no observable effect. Quantum chemical calculations at the HF/6-311+G(2d,p) and B3LYP/6-311+G(2d,p) levels, with the inclusion of solvation effects via the isodensity polarizable continuum model (IPCM), correctly reproduced the experimentally observed trends but failed to account for some of the measured rotational barrier's magnitudes. Hydrogen-bonding effects were included by performing molecular dynamic simulations. For these latter calculations, it was necessary to parametrize the force field against energies of water-solute complexes calculated at B3LYP/6-31+G(d,p). Through the results of radial distribution functions, solution rotational barriers could be calculated, presenting good agreement with experimental determinations and revealing the role of hydrogen bonding. Interestingly, only for 2, the rotational barrier is predicted to increase as a result of complexation with water. For the remaining compounds, hydrogen bonding causes the barrier to decrease, contrasting with most of the molecular systems studied up to now.

show abstract

Hindered rotation in some organometallic carbamates, thiocarbamates, and dithiocarbamates

Cited by 44 publications

References 3 publications

Chalcogen Extrusion from Heteroallenes and Carbon Monoxide by a Three-Coordinate Rh(I) Disilylamide

Chalcogen Extrusion from Heteroallenes and Carbon Monoxide by a Three-Coordinate Rh(I) Disilylamide

Pyrrolidine dithiocarbamates of Pd(II)

Medium Effect on the Rotational Barrier of Carbamates and Its Sulfur Congeners

Contact Info

Product

Resources

About